Field of the Invention
The present invention relates to a method of manufacturing a liquid ejection head and a liquid ejection head, and more specifically to a joining method for the case of joining a print element substrate, which is provided with an ejection port for ejecting a liquid such as ink, to a supporting member.
Description of the Related Art
Japanese Patent Laid-Open No. 2012-240210 discloses the technique for use in manufacturing a liquid ejection head for ejecting a liquid such as ink, which reduces a spill-out of an adhesive agent at the time of joining a print element substrate to a supporting member by an adhesive agent. More specifically, in Japanese Patent Laid-Open No. 2012-240210, in order to join the print element substrate to the supporting member, an adhesive agent is applied on a joining surface of the supporting member in the first place. Then, the print element substrate is brought into contact with the adhesive agent at the position above the joining surface for a predetermined height. In this instance, a convex portion is provided on the supporting member so that the print element substrate is brought into contact with the convex portion to join them to each other, thereby preventing the adhesive agent from being squished beyond necessary. This can prevent a redundant adhesive agent from being spilled out in a liquid flow path by squishing. As a result, it is possible to prevent the problem before it occurs, in which a liquid flow is blocked by the redundant adhesive agent spilled out in the liquid flow path and involves and traps. Suppressing the spill-out of the adhesive agent in this manner is particularly effective in a downsized liquid ejection head which is provided with a relatively narrow liquid flow path formed in the supporting member.
Then, the adhesive agent described above may contain filler for adjusting the viscosity, and the filler may be coagulated to form an aggregate of several tens of micrometers in size. In this case, the technique in Japanese Patent Laid-Open No. 2012-240210 may cause a problem in which the print element substrate cannot be correctly joined to the convex portion on the supporting member due to such an aggregate.
More specifically, as shown in FIGS. 1A 1B and 1C, in Japanese Patent Laid-Open No. 2012-240210, a convex portion 116 is provided on a supporting member 109. When a print element substrate 101 is bonded to the supporting member 109 by an adhesive agent 104, an aggregate 105 generated in the adhesive agent 104 may be sandwiched and included between the convex portion 116 and the print element substrate 101 at the position where the distance must be zero. In consequence, the print element substrate 101 cannot be appropriately brought into contact with the convex portion 116, so that the amount of spilled adhesive agent cannot be appropriately controlled. In addition thereto, the bonding itself may be inappropriate. As a result, the problem of leakage of the liquid will arise in which the adhesive agent runs out through an inappropriate portion, for example, thereby reducing production yields.
In addition, in order to prevent the problem described above before it occurs, it can be considered that the aggregate is crushed so as to bring the convex portion into appropriate contact with the print element substrate. This requires, however, a relatively large force, such as 20N. In this case, the crushing force results in damage given to the print element substrate, or misalignment of bonding position of the print element substrate.